Safety tractor stop



May 1, 1951 E. HOFFMAN ET AL SAFETY TRACTOR STOP I 3 Sheets-Sheet 1Filed Jan. 21, 1949 v Edwin Hoffman 8 mm N Hm mm E M a P May 1, 1951 E.HOFFMAN ETAL SAFETY TRACTOR STOP 3 Sheets-Sheet Filed Jan. 21, 1949Edwin Hoffman Paul E. Hoffman INVENTORJ May 1, 1951 Filed Jan. 21, 19493 Sheets-Sheet 3 4a /a 48 Z;

y 42 {E I 46 5a 5a 42 g M 0? 20* {If /2 "j ;2}n Edwin Hoffman V Paul E.Hoffman 26 26' INVENTORJ' Patented May 1, 1951 SAFETY TRACTDR. STQPEdwin Hoffman and PauliEHoffman, Defiance, Ohio Application January 21,19.49, SerialjN0.:71;804

'2'Claims. .1

.This invention relates to noveland useful improvements in attachmentsfor tractors.

An object of this invention is to render a tractor inoperative underemergency conditions automatically by several cooperative meansincluding a switch which is responsive to the weight of an individualnormally seated on a conventional tractor seat and by the weight of anindividual foot pressingon a foot rest.

Another object of this invention is to render a tractor capable ofbecoming operative when one of the aforementioned forces is present andalso providing a structural arrangement wh reby the tractor may berendered operative in the absence of one of these 'forces by utility ofa holder or stop which retains one of the switches forming a portion ofthe structural makeup of the invention in the'open position.

Another object of this invention is to supply a number of switches inthe'conventional electrical circuit of a tractor, which switches areretained normally in the closed position-therebygrounding the usual andconventional electrical circuit of a tractor until such time that aforce is applied to the physical switches thereby opening them andcompleting the circuit, all of the switches being provided in series,whereby the tractor may be rendered operative by opening any one or allof the switches.

Another object of this invention is to supply an extremely simplifieddevice of the character to be described which is practical from thecommercial standpoint and also from the operational standpoint.

Ancillary objects and features of novelty will become apparent to thoseskilled .in the art, in following the description of the preferred formof the invention, illustrated in the accompany ing drawings, wherein:

Figure 1 is an elevational View of a fragmentary portion of a tractorhaving the-preferred form of the invention applied thereto;

Figure 2 is an enlarged fractional portion of the device shown in Figure1, showing a second operative position thereof;

Figure 3 is a fragmentary plan view or" a tractor. showing theinventionapplied thereto and taken substantially on the line-B of Figure l in thedirection of the arrows;

Figure 4 is a sectional View illustrating one of the switches andv itsstructural connection-wither portion of a tractor andtakcnsubstantially-on theline i t oiFrigure 3 .andin-the directionzof thearrows;

Figure 5 is anelevational view ,taken substantiall-y on the line- 5.5 ofFigure 1 and in the. di

rection of the arrows;

Figure (i-is an enlarged: sectional view illustratingdetails of one ofthe switches taken. substan- 5 tially-onthe;line6.5 of Figure5andinthe'di- ;rection of the arrows;

:Figure 7 is a-.sectional-view similar to that shown intFigure 6, theoperative elements of the switch and associated :mechanism being ,in asecond position; and

Figure 8 is a schematic viewillustrating a wiringdiagram including aportion of the-conventional electrical circuit ofja tractor and theadditional wiring necessary in the application of the device to atractor.

Structurally, it is necessary that .a-device for use in conjunction withfarm equipmentbe extremely simplified as well as eflicient and practicalbefore it is commercially feasible. Hence, this is one of theprimeintents of the present invention.

A conventional tractor generally indicated at It! .is illustrated'as thepreferred environment for use with the invention. -The tractor includes-(shown.schematical1y in FigureB) an engine l2 .ha-vin-gyadistributorror-magneto :14 as a necessary adjunct for usetherewith. -Ahot wire l6 sextendsfrom the magneto shown in Figure 8 and terminates ata .switch generally indicated-at I8. Inthe ordinary electrical circuit,this hot wire would not lead ,to.a switch but would lead to anothercomponent of the tractor which is un- .important in so faras thezadaptability of the gpresentdevice-is concerned, or is a simple groundwire.

As is seen,,switches 2.0,:22;ZL-andZGaresup- .pl-ied in series with'thesaid switch l8, whenone of the wires is grounded .toasuitable elementshown schematically'as a bolt 28. This bolt is, of course, fixed to thetractor whereby the tractor frameis used as a ground.

All'of theswitches being in series, it is apparentrthatgone;orsmoreoftheswitches are opened, current will not fiowto theground bolt 28. Hence, the hot wire I6 is rendered ineffectual for the.purpose of. grounding the: magneto or "distributor and theordinarycircuit is permitted to'function as a TCOZHplEtE circuit. But, when all'of :the switches. areiintherposition as shown in Figure 8, the magneto.is; groundedtherebyrendering it impossib-lefo-iithe; engine .to operate.

in order to oper-ate the ;said -.switches .many structural arrangements;may "be .resorted to. .Shown in .Figure 3 isonelarrangement..Thiszarrangementincludesrapair.of platesiwand 32, re-

spectively, which are connected at their inner edges by means of hinges34 and 36 to a portion 38 of the tractor frame or chassis. Switches l8and 20, respectively, are carried by the plate 39 while switches 25 and24 are carried by the plate 32. These plates serve as foot rests for anindividual seated on the seat 40 when operating the tractor. Hence, uponapplication of a force to either of the plates 30 or 32, the switchesare depressed thereby opening them and allowing the tractor engine tofunction.

Reference to Figures 6 and 7 shows the specific structure of theswitches. A small housing 42 is fixed by any suitable means such asrivets, welding, bolts, etc., to the under surface of the plate 3!} andhas a pair of openings therein for the passage of the wires connectedwith the switch I8. Grommets 44 may be supplied in order to properlyinsulate the wires.

A plunger ii-i is slidable through an opening in the small housing 42and is guided by means of a fiange 48 fixed thereto around the saidopening. An arm or plate 50 is fixed to the plunger 45 and is movabletherewith. A screw 52 may be used in fixing the arm 50 to the saidplunger 46. An annular flange 54 is integrally carried by the arm 56 andforms a seat for a Spring 56 or other resilient urging means. One end ofthe spring seats in the annular flange 54 and the other end reacts onthe bottom surface of the plate 39, constantly urging the plunger itoutwardly of the housing as seen in Figure 7. Contacts 58 and 663,respectively, are carried by the arm 50 and the said housing 42 and areinsulated therefrom by means of electrically insulating grommets or thelike. The said leads or wires described above terminate in an electricalconnection with the said contacts 58 and 60.

With the spring 56 constantly urging the plunger 46 outwardly of thehousing, the under surface of the plate 50 forms a stop when it coactswith the guide 43. However, at this time the contacts 58 and 68 are inelectrical communication with each other thereby grounding theelectrical circuit through the structure of the switch including theplunger 46 which is in contact with a portion 33 of the tractor frame orchassis.

The seat 45 is attached to a support 62 by a conventional adjustingmechanism. This support is carried in the bight 36 of a hold-down memberfor pivotal movement and opposed by the resiliency of a spring 68. Thebight of the holding bracket has a pivot pin passing therei through andalso through the appropriate end of the support 52. with the support 62and has a nut at one end backed by a retainer it. The said spring 88reacts on the retainer and the bight 66.

A strap (Figure 4) i8 is secured to the said support (32 and carries thesaid switch 22. Any

suitable fastening means may be used in this connection such as a bolt,spot-welding, etc. In operation, it is noted that as soon as a force isapplied to the seat 49 such as by means of the weight of an individual,the support 62 is depressed thereby moving the plunger 80 of the switch22 downwardly against a portion of the tractor chassis or frame. Thisspreads the contacts in this switch 22 as described in connection withthe switch i8 shown in Figures 6 and 7.

In operation thus far described it is seen that a tractor will notoperate unless a force is applied to one of the variously describedcomponents in order to open at least one of the switches. This, ofcourse, indicates that as soon as adverse A bolt '12 is fixed formovement conditions arise as by the operator of the tractor fallingtherefrom, the tractor becomes immediately inoperative. Occasion mayarise, however, wherein it is desired to utilize the power take-cit of atractor without an individual seated thereon. Also, it is appreciatedthat certain repairs and adjustments must be made on tractors. Underthese conditions a means for rendering the attachment ineffectual issupplied. Accessible means consists of a holder mechanism generallyindicated at which is fixed to one of the conventional pedals of atractor and to one of the plates 3!! or 32.

Manufacturers of tractors and/ or land vehicles in general advise thatthe clutch plate of the tractor be disengaged before attempting to startthe engine. With this in View the clutch arm 82 is chosen as therecipient of the hold-down mechanism.

An arm 83 is pivoted to a bracket 86 which, in turn, is secured to theoperating arm of the clutch mechanism. A compression spring 88 is fixedat one end to the arm 3% and at the other end to another bracket 89. Thesaid bracket 89 is carried by the operating arm 82 constantly urging orbiasing the arm 3s upwardly with respect to the floor of the tractor.One or more keepers 9B which are similar to teeth are provided on theupper surface of the plate 32 for operative engagement with the end ofthe arm 84.

In operation, the plate 32 is depressed thereby opening the switches 26and 24. Then, the arm 84 is simply disposed between the keepers 3i!thereby holding the plate 32 in the down position.

In order to release the holder mechanism 89 it is'necessary only todepress the clutch pedal 82 downwardly the full amount, thereby slidingthe arm 84 in such position that it clears the last keeper Bil and thespring 83 urges it to the up position entirely free from contact withany of the keepers 90.

It is apparent that many variations may be made without departing fromthe spirit of the invention. Also, certain elements may be added forsmoothness of operation, such as the springs 92 shown in Figure l whichconstantly urge the plate upwardly rendering it necessary to apply apositive force to the plate rather than any jarring force which mightoccur during conventional operation of a tractor over a field.

In view of the foregoing limitation is sought only in accordance withthe scope of the following claims.

Having described the claimed as new is:

1. In combination with a tractor which has a longitudinal axis, acontrol pedal pivoted to the tractor and a dog mounted for pivotalmovement on said pedal, a plate hinged for movement along an axisparallel to the longitudinal axis of the tractor and forming a foot restplate, teeth dis-- posed on said plate and engaged by said dog to holdsaid plate in a predetermined position when said pedal is depressed, aspring secured to said dog and said pedal normally urging said dog intoengagement with said teeth, resilient means opposing the operation ofsaid plate and reacting on the tractor, a switch operable between saidplate and the tractor and operatively connected with a portion of thetractor for controlling the operation of said tractor in response tomovement of said plate.

2. The combination of claim 1 and a second invention, what is REFERENCESCITED The following references are of record in the file of this patent:

Number 6 UNITED STATES PATENTS Name Date Nafziger Dec. 27, 1932 NafzigerMay 1, 1934 Ranlett Mar. 31, 1936 Richter Feb. 9, 1937

